Odd nut/screw/bolt/retainer? Read post for description...

[Superslinky]

I've come across an odd screw in a valve. I think it might be called a valve retainer screw but I'm not sure.

It appears to have a 7/8-20 thead, is 1/4" in length and has an 5/16" allen hex completely through the center. Can anyone point me in the right direction?

Thanks....

 

[TVP]

Does it look like one of these?

http://www.google.com/search?hl=en&...&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi

 

[JStephen]

"Hollow Lock Set Screw"

http://www.mcmaster.com/#91301a037/=dc1crs

 

[unclesyd]

Though I tend to go with being part of an adjustment system another possibility is that this may be a valve seat. Many, many years ago the company I worked for made valve seats with both square and hex holes.
If it had a very thin bottom it could be an orifice as we use set screw or internal pipe plug with a thin bottom for making small orifices for steam. Using the hex drive makes it easy to change out.

 

[Superslinky]

Thanks guys, I had already found similar results to the links TVP and JStephen provided. unclesyd, I beleive it is called a valve seat. The thread and diameter make it different than that of what can be found on McMaster and other hardware vendors. Are there vendors for these types of hardware or are the "special" to the manufacturers of valves? If it is a valve seat, what can I use in its stead if I am unable to find one.

Thanks again guys...

 

[unclesyd]

A valve seat is normally classified as a replaceable part so the manufacturer or their distributor should be able to provide you a replacement. This would be like replacement seats for a lot of compression type water valves including the faucets in your house unless the seat is integral with the body. There are also a lot of plumbing supply companies that supply parts for various valves.
The last resort would be to send it to a valve repair facility and let them worry about it.

Another approach would be to refinish the existing seat by in place grinding.

Another thing to remember is most of these seats are installed with some type of thread locker so they can be hard to remove and you have to really clean the threads before install a replacement.